Dopant Thermochemical Conversion Pilot Study

With economic development and social progress, the energy shortage and environmental pollution problems also follow. Biomass energy will play an important role at present and future human sustainable energy development system,because of its congenital advantages. As the major product of eutrophication lakes and other water areas, cyanobacteria not only destroys ecological balance, but also seriously endangers human living environment and the health. Therefore, cyanobacteria was transformed into bio-fuel with thermochemical conversion in this research, in order to achieve economic, social and environmental development of a win-win situation.At first,pyrolysis of cyanobacteria from Dianchi lake was investigated by TG-DSC-FTIR analysis at different heating rates (10,20,40℃/min). The results indicated that the pyrolysis of cyanobacteria can be divided into four stages: evaporation, depolymerization, devolatilization and carbonization. Meanwhile, the initial weight-loss temperature, weight-loss extreme position, endothermic and exothermic peaks were moved to higher temperature with the increaseing of the heating rate. The kinetic analysis was made with Popescu method. It indicated that the best kinetic model for the pyrolysis of cyanobacteria was the cylindrical symmetry of the phase boundary reaction model. The main pyrolysis gases checked with real-time online FTIR were HCN, NH3, CO, CO2, water vapor and hydrocarbons.In addition,the experimental researches on thermochemical liquefaction of cyanobacteria were carried out in different solvents(water, ethanol,the mixture of ethanol and water).The results showed that the highest total conversion (94.5%)and bio-oil yield(41.3%) were obtained at 380℃and 1:20g/ml when cyanobacteria was liquefied in water for 40min,the main compounds of liquefaction product were aromatic, pyrrole and pyridine derivatives; the highest total conversion (86.6%)and bio-oil yield(35.7%) were obtained at 270℃and 1:15g/ml when cyanobacteria was liquefied in ethanol for 30min,the main compounds of liquefaction product were fatty acid ethyl ester and other esters with nitrogen; the highest total conversion (92%)and bio-oil yield(42.5%) were obtained at 320℃and 1:15g/ml when cyanobacteria was liquefied in the mixture of ethanol and water for 30min,the main compounds of liquefaction product were aromatic, pyrrole and pyridine derivatives.fatty acid ethyl ester and other esters with nitrogen,and a little amide.At last,the bio-oil and residue were detected by using different analysis means, it was assumed that the bio-oil was mainly transformated from protein and crude fat of cyanobacteria, the liquefaction mechanism may have the following seven ways:crude fat hydrolysis, protein hydrolysis products further reaction, crude fat hydrolysis into fatty acids esterified with ethanol,and proteins hydrolysis into amino acids esterified with ethanol, organic acids extracted from crude fat in (near) super-criticle solvent esterified with ethanol, fatty acids decomposed from crude fat in (near) supe-rcriticle solvent esterified with ethanol, amino acids decomposed from protein in (near) super-criticle solvent esterified with ethanol,the reaction of fatty acids with amino acids.